Electric connector for the motor of a hermetic compressor

ABSTRACT

An electric connector for the motor of a hermatic compressor, comprising an electric insulating body seated against the stack of lamination ( 6 ) of the stator of the electric motor, and carrying a plurality of binding posts ( 22 ), which receive and affix respective wires from the coil windings ( 7 ) of said stator of the electric motor; contact terminals, eletrically connected to the binding posts ( 22 ), and which will be connected to the hermetic compressor, by respective conductors ( 30 ); and at least one fixation means ( 23 ), which is fitted and immobilized in a retaining bore ( 11 ) provided in the stack of lamination ( 6 ) of the stator.

FIELD OF THE INVENTION

[0001] The present invention refers to an electric connector for theelectric motor of a hermetic compressor of the type used inrefrigeration appliances, such as refrigerators, freezers, waterfountains, etc., for connecting inside the hermetic shell of thecompressor the coils of the electrical motor to a power inlet plugprovided in the shell of the compressor.

BACKGROUND OF THE INVENTION

[0002] The motor of a hermetic compressor usually comprises, mountedinside its hermetic shell, a rotor and a stator, the latter being formedby a main coil and a secondary coil, said motor being fed by an electriccurrent from a power source external to said hermetic shell, byconnecting an appropriate wiring to a power inlet plug, mountedexternally to the hermetic shell and which is electrically connected tothe stator of the electric motor.

[0003] In a known construction, in order to connect the stator to thepower inlet plug of the hermetic shell through the interior of thelatter, some copper wires of the stator, generally three, are connectedto a cable by clamping a metallic piece, joining each copper wire to thecable, which is then connected to the shell. After clamping the twoparts together, for each wire, the formed assembly receives a thermalretractible insulating cover, which protects said connection thusobtained. After the connection, the whole assembly is positioned insidethe coils that form the motor.

[0004] This construction presents some disadvantages, such as difficultautomation, for example in the clamping steps, which also results in lowquality of the obtained electric connections, with a high number ofdefects and rejections, for example due to low efficiency of theintended connection and to failures in the process for obtaining saidconnection.

[0005] In another known construction, the electric connections of themotor to the shell of the compressor occur through an electricconnection device, which receives each copper wire from the motor coilsto be electrically connected to the shell of the compressor, and whichlodges each of said wires in a respective contact cradle. While thissolution allows for automation and improves the quality of the electricconnections between the motor and the hermetic shell of the compressor,as compared to the electric connections obtained by clamping, the knownconstructions for an electric connection device present deficiencies inrelation to the form of retaining said devices inside the hermetic shellof the compressor.

[0006] In one of the known solutions for affixing the electricconnection device inside the hermetic shell of the compressor, one ofthe parts which forms said device and which is provided with teeth isaffixed, by interference, in the stator of the electric motor. Inanother known solution, the part to be affixed to the stator is providedwith flanges, which are fitted into a portion of the stator, beforefastening thereof.

[0007] In the first fixation option, the disadvantages reside in thefact that the fixation means is easily broken, due to aging of thematerial, generally plastic, and the possibility of occurring relativemovements between the electric connection device and the stator wire,which can lead, with time, to material fatigue. Moreover, thisconstruction allows the occurrence of undesired vibrations in theconnection. In the second fixation option, the disadvantages result fromthe fact that, for each flange of the electric connection device to befastened to the stator, there is loss of a fastening point thereof. Inthe known fixations, three fastening points of the stator are lost withthis process.

SUMMARY OF THE INVENTION

[0008] Thus, it is an object of the present invention to provide anelectric connector for the motor of a hermetic compressor, which allowsa safe and strong fixation thereof to said electric motor, without thedisadvantages of occurring ruptures or fatigue, or impairing thefastening of the stator.

[0009] It is a further object of the present invention to provide anelectric connector with the characteristics mentioned above, whichallows obtaining the desired electric connection in a substantiallyautomatized form.

[0010] These and other objects are attained by an electric connector forthe motor of a hermetic compressor, said motor being mounted inside ahermetic shell and comprising a stator formed by a stack of overlappedlaminations lodging coil windings, said shell carrying a power inletplug to be connected to a current supply source, said electric connectorcomprising an electric insulating body, seated against the stack oflaminations of the stator and carrying: a plurality of binding posts,which receive and affix respective wires of the coil windings; contactterminals, electrically connected to the binding posts and which will beconnected to the power inlet plug of the shell by respective conductors;and at least one fixation means, which is fitted and immobilized in aretaining bore provided in the stack of laminations of the stator.

BRIEF DESCRIPTION DRAWINGS

[0011] The invention will be described below, with reference to theenclosed drawings, in which:

[0012]FIG. 1 shows, schematically, a longitudinal diametrical sectionalview of a hermetic compressor of the reciprocating type with a verticalshaft, presenting an electric connection between the motor and the shellof the compressor, using the electric connector of the presentinvention;

[0013]FIG. 2 shows, schematically, an upper view of the stator of theelectric motor, the windings of said stator and the wires forelectrically connecting the windings being prepared for connecting thehermetic shell of the compressor, according to the prior art;

[0014]FIG. 3 shows, schematically, a lower view of the stator of theelectric motor, presenting the stator, the windings of said stator andthe wires for electrically connecting the windings being prepared forconnecting the hermetic shell of the compressor, using the electricconnection of the present invention;

[0015]FIG. 4 shows, schematically, a front view of the electricconnector of the present invention, before its assembly to the stator;

[0016]FIG. 5 shows, schematically, a lateral longitudinal sectional viewof part of the electric connector of the present invention; and

[0017]FIG. 6 shows, schematically, and in an upper view, the electricconnector of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

[0018] The present invention will be described now in relation to areciprocating compressor used in refrigeration systems and of the typehaving a vertical shaft (FIG. 1), comprising a hermetic shell 1, insidewhich is suspended, in an appropriated manner, for example by springs, amotor-compressor assembly formed by a cylinder block 2, to which isaffixed an electric motor, whose rotor 3 is fixedly mounted to avertical crankshaft 4 supported on a main bearing, which is machined inthe cylinder block 2. The crankshaft 4 sustains, at the lower portionthereof, a pump rotor, which carries oil from an oil sump 5 to the partsof the cylinder block 2 requiring lubrication during the operation ofthe compressor.

[0019] The electric motor of the compressor comprises, besides the rotor3, a stator formed by a stack of laminations 6, which are metallic andin overlapped alignment, so as to define axial housings to receive coilwindings 7 from the electric motor.

[0020] The electric motor is fed with current from an appropriate andnot illustrated current source, by electrically connecting said currentsource with a power inlet plug 8, carried by the shell 1 and which iselectrically connected to the electric motor of the compressor.

[0021] According to the present invention, the stator carries, fixedlyseated against its stack of laminations 6, for example in one of the endlaminations thereof, an electric connector 20, to be described ahead andwhich, by means of conductors 30, electrically connects the electricmotor of the compressor to the power inlet plug 8.

[0022] The electric connector 20 of the present invention comprises anelectric insulating body, which defines a plurality of housings 21, eachcarrying a binding post 22, which receives and affixes respective wiresof the coil winding 7, said electric insulating body carrying contactterminals, electrically connected to the binding posts 22, and whichwill be connected to the power inlet plug 8 of the shell 1 by respectiveconductors 30, such as for example a conventional wiring, having a firstend 31, for connecting the electric connector 20 of the presentinvention, and a second end 32, for connecting the power inlet plug 8 ofthe compressor.

[0023] The electric connector 20 of the present invention furthercomprises, carried by its electric insulating body, for exampleincorporated or retained therein, at least one fixation means 23 to befitted, for example by interference, into a retaining bore 11 providedin the stack of laminations 6 of the stator, in order to be immobilizedin relation to the latter, when introduced into said retaining bore 11.

[0024] According to a way of carrying out the invention, the retainingbore 11 is a bore made during manufacture, already existing in the stackof laminations 6 when the present electric connector 20 is installed,and which is axially defined in said stack of laminations 6, externallyto the housings that receive the coil windings 7, during production ofsaid stack of laminations 6, said retaining bore 11 having a certaindiameter “d”, which is previously calculated so as not to interfere withthe metallic mass of the stack of laminations 6.

[0025] The illustrated fixation means 23 is in the form of a projection,inferiorly extending from a portion of the insulating body of theelectric connector 20 of the present invention, and which is providedwith extensions of external circumferential ribs 24, along a substantialportion of the axial extension of said projection, said externalcircumferential ribs 24 being parallel and aligned to each other andresiliently flexible, in order to be introduced into the retaining bore11. The external circumferential ribs 24 define, for the fixation means23, a diameter “D” that is superior to that of the retaining bore 11, inorder that, after introducing the projection inside the retaining bore11, the efforts to remove said projection will require a modification,in the angular positioning of the external circumferential ribs 24,which surpasses the diameter of the retaining bore 11, thus immobilizingthe present electric connector 20 in relation to the stator.

[0026] According to the present invention, the electric connector 20presents, carried by the electric insulating body, a support stop 25,angularly projecting from a rear portion of said insulating body, andwhich will be seated on an adjacent portion of the coil windings 7 ofthe stator, upon fixation of the present electric connector 20 to thestack of laminations 6 of said stator, said support stop 25 being, forexample, fastened to said coil windings 7 upon fastening of the latter.

[0027] The support stop 25 is a constructive option, which allows thepresent electric connector 20 to be more safely retained to the stator,and which, even though being fastened to the coil windings 7 of thestator, only suppresses two points of the fastening thereof, whichpoints are used for fastening said electric connector 20 to the stator.

[0028] The electric insulating body of the present electric connector 20further has at least one front flange 26, defining a guide forpositioning the connector in relation to the stack of laminations 6, andwhich will be seated against an adjacent external wall portion of thestack of laminations 6 of said stator.

[0029] According to the illustrations, the insulating body of theelectric connector 20 of the present invention defines, close to thehousings 21 that receive the binding posts 22, the electric contactterminals, which connect the electric terminals of the first end 31 ofthe electric conductor 30 to be connected to the power inlet plug 8 ofthe shell 1 of the compressor. According to the illustrations, thehousings 21 for contacting the present electric insulating body are ofthe type having an upper inlet 27 with a “V” profile, whose vortexportion opens to a cradle 28, which receives a wire portion of the coilwinding 7, retaining said wire portion and avoiding movement thereof, aswell as avoiding possible ruptures due to fatigue resulting fromvibrations of the compressor during operation thereof.

1. An electric connector for the motor of a hermetic compressor, saidmotor being mounted inside a hermetic shell (1), and including a statorformed by a stack of laminations (6), which are overlapped and lodgecoil windings (7), said shell (1) carrying a power inlet plug (8) forconnection to a current supply source, characterized in that itcomprises an electric insulating body, seated against the stack oflaminations (6) of the stator and which carries:—a plurality of bindingposts (22) which receive and affix respective wires from the coilwindings (7);—contact terminals, electrically connected to the bindingposts (22) and which will be connected to the power inlet plug (8) ofthe shell (1), by respective conductors (30); and at least one fixationmeans (23), which is fitted and immobilized in a retaining bore (11)provided in the stack of laminations (6) of the stator.
 2. Device,according to claim 1, characterized in that the insulating body isseated against one of the end laminations of the stack of laminations(6) of the stator.
 3. Device, according to claim 2, characterized inthat the retaining bore (11) is axially provided in the stack oflaminations (6) of the stator, externally to the coil windings (7). 4.Device, according to claim 3, characterized in that the fixation means(23) is fitted, by interference, into the retaining bore (11) of thestack of laminations (6).
 5. Device, according to claim 4, characterizedin that the fixation means (23) is in the form of a lower projection ofthe insulating body, said projection having extensions of externalcircumferential ribs (24).
 6. Device, according to claim 5,characterized in that the retaining bore (11) presents a diametersmaller than the diameter of the projection containing the extensions ofthe external circumferential ribs (24).
 7. Device, according to claim 6,characterized in that the extensions of the external circumferentialribs (24) are parallel and aligned to each other, and resilientlyflexible for introduction into the retaining bore (11).
 8. Device,according to claim 1, characterized in that it comprises a support stop(25) coupled to the electric insulating body, and which will be seatedon the adjacent coil windings (7) of the stator.
 9. Device, according toclaim 8, characterized in that the support stop (25) is fastened to thecoil windings (7) of the stator.
 10. Device, according to claim 9,characterized in that the support stop (25) is a rear projection of anupper portion of the electric insulating body.
 11. Device, according toclaim 10, characterized in that the electric insulating body is providedwith at least one front flange (26) defining a guide to be seatedagainst an adjacent external wall portion of the stack of laminations(6) of the stator.
 12. Device, according to claim 1, characterized inthat the contact terminals are defined by the binding posts (22).